The number 20428
20428 is a composite number with 6 divisors. Its prime factorisation is × 5107. Divisors (6): 1, 2, 4, 5107, 10214, 20428.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
20428 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
20428 is composite. Its prime factorisation is
- 3
The divisors add up to 35756; without 20428 itself that is 15328, so 20428 is deficient (15328 is less than 20428). Euler's totient φ(20428) = 10212 numbers up to 20428 share no factor with it.
- 4
The digits of 20428 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 180 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20428 = 2^{2} \times 5107 \]20428 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 35756 |
| Euler totient φ(n) | 10212 |
| Square | 417303184 |
| Cube | 8524669442752 |
| Square root | 142.926555 (= 2√5107) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 180 |
| Scientific notation | 2.0428 × |
20428 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand four hundred and twenty-eight |
| Binary (base 2) | 100111111001100 |
| Octal (base 8) | 47714 |
| Hexadecimal (base 16) | 4FCC |
| Base 3 | 1001000121 |
| As time | 20428 seconds = 5 h 40 min 28 s |
Is 20428 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (20428 ÷ 2 = 10214) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (20428 ÷ 4 = 5107) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | No (remainder 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20428 a prime number?
No. 20428 = × 5107, so it is divisible by 2.
What are the factors of 20428?
1, 2, 4, 5107, 10214, 20428.
What is 20428 in binary?
100111111001100 (hexadecimal 4FCC, octal 47714).
What is the square root of 20428?
About 142.9266, exactly 2√5107.
Is 20428 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 20428?
It is a composite number with 6 divisors.